I just wanted to see if any Canada members or US members have ever had any problem shipping any AR parts to Canada. The reason I ask is someone is going to buy a A2 upper receiver from me (no barrel) and I wanted to make sure I would not run into any export problems or issues with this. Any problems with just shipping a upper receiver to Canada? The guy seems very honest and I do believe him but sinde it is a different country and in the current age we are in. I just wanted to make sure it was OK. Thanks

I sold a Bushmaster upper here on EE to a Canadian who swore it was ok, but insisted that I ship to his "Mailboxes Etc." box just over the border in North Dakota. Makes you wonder, but that was fine with me. Better safe than sorry.

As far as importing into Canada, there is no regulations concerning any component of the AR-15 with exception for the lower receiver which is serialized and trigger groups must be semi only. Here the AR-15 is considered in the same group as handguns and is regulated as such, however only the lower receiver is registered.
That being said, there is a second part to the equation, exporting out of the USA. The State departement has many regulations concerning firearm major components, and in the last year has increased the list of items requiring an export permit. Items designated as dual purpose use require an export permit, some of these items include railed handguards, scope mounts, sights, optics... It has gotten almost imposible for a person to buy items from the US, Canadian dealers have had to wait months for export permits to get stock.
Now to answer your question as to why use a US mailing address, well, if you as an americain ship to Canada, you need to fill out the couriers (UPS, Fed-X..) international shipping docs which will include description of items and also a declaration that shipped items that are regulated by the State department have the appropriate export permits or face possible prosecution. However, if Joe Canadian drives to the US and picks up his gear then drives back, he is not dealing with US customs but only with the Canadian customs, and since Canada has no issues with these items you just pay up the taxes and custom fees. (depending on the item, you may run into a Canadian custom officer who does not no the law or does not know the difference between a barrel and a lower receiver)
800mtrs - If you ship the upper receiver to Canada and your docs describe the item as such the broker might refuse to clear it, but then again maybe not. Not everyone is clear on the items and a gray area exists, but an upper is definetly a major firearm component and is limited to a $100us value without the requirement of an export permit (this has been the rule over the last many years, the